Improvement in ruler attachments for drawing-boards



T.A BBRGNBR. RULBR ATTACHMENT TOR DRAWING BOARDS.

No. 113,726. Patented Apr. 1'8, 1871.

A" "A" 'MHAWM "'fTHEODGR-E BERGN ER," 0F PHI-LA DELPHA, PE NSYLVANIA,y ASSIGNOR TO JAMES W. QUEEN a (30;. OF SAME PLACE,.-

Laers Patent No. 113,726,11atea April 18,is71.

lwnvacbvsrvfi.enr in RULER Ail-TuraniEnrs- FOR DRAWING-somos.

' The Schedule referred to in these Letters Patent and making part of the same.

' the edges of the drawing-board, as is the case with .the ordinary Tsqultre. rlhis part of' my invention also comprises a means of setting the parallel-ruler at different angles to the head, and the means of' securing the head or cross-piece in any position in the direction oi' its motion on `the board., and relative to the angular adjustment of the ruler.

The second part of' mv invention relates to the combinatiolr, with a drawingLboard and-the improved par alll-rnler, cfa system of 'graduation or scales7where by the vertical, horizontal, and angular measurements or divisions may be defined on the drawing Without the use of compasses and detached scales.

In the annexed drawing forming part of' this speciiication Figure l is a plan of my improved drawingboard.

Figure 2 is a section on the line :I: i fig. 1.

; Figure 3 is a transverse section through the line az,

A is a plain rectangular board, ot'nniform thickness, which' may be of any required dimensions, and when `large should be made up of' pieces framed together so as to prevent warping.

This board is, cu the'nnder side, provided with two `bars or straightedges, 'b and il', placed parallel to and equidistant from the vertical center-line of the,.board, and acting as guides for the sliding head C, whi'ch is confined between their opposite inner edges.

D is a 'supplementary ruler, jointed to this head at d, and carrying the drawing-blade or ruler E,which is tted at each end to pins e e, and rests on intermedi ate blocks f j', of the required height f'or keeping the two rulers level when the upper one, E, rests on the top of the board.

The weight of' head C and blade D is supported by the laterally-prqi-ecting edges of a thin plate of' metal,

G is vernier, by means of which the deflection of l correctly measured upon the degree-scale ofF.

. One of the straight-edges, b, is permanently secured to theboard A, whilethe other, b', is-so held against the board by clamping-screws and washers 'i fi that it may have a limited sliding motion onA its bearing surface, for the purpose of adjusting the guiding surfaces relative to head O.

J jj are springsv resting in suitable' cavities under the bar .b, and bearing againstpins k k ou bar b' with a "tendency of pushing the guiding snrf'aceof this bar 'away from the opposite guiding surface on bar b.

H H are small cams, secure-d to board A by screws v "v, acting as4 fulcrums for their v ibratioing The bar b being held against the eccentric surfaces of these cams by the elastic pressure of springs jj, and capable of movement under the washers ofclamping-screws serves on the one hand to compensate for shrinkageor swelliugpf' .the several parts', or for wear ofthe shding surfaces, to preserve their parallelism, while on the head C securely between its guiding surfaces at any point in the direction of its motion. The object 'and importance of this arrangement will be readily appa in any desired place on. the board, the drawing or inking of vertical shading linesror the drawing of equi. distant hues for shading or sections, can be accomplished with ease andaccuracy, iti-[being only necessary to slide the triangle along the fixed edge ofthe ruler without attention to the position of the latter, whereas with the use of an ordinaryT-sqnare, or with-` out this means of securing myimproved ruler,a more diversified attention and greater skill are required to do such work accurately and with dispatch.

The improved mode of guiding the parallletruler has important advantages over the T-square xn other respects: To draw parallel lines with the latter requires aconstant eort to press it against the edge of the board; and 'when the extreme end of its rule is used, or when lines are to be drawn near the top or bottom edge of the board, its use becomes very inconvenient v, and unreliable; whereas myimproved drawing-ruler is lelism, and remains uniformly correct and convenient in any position over the whole field of' the board.

. In order to provide a clear space underneath the drawinghoard for the free motion of head C and lower ruler D, the board has three feet or supports, Z m m.

l is fixed at the top on a cross-piece', n. beneath the upper end of' bars b b'.

The two lower supports, mm, are carried on slideso o,

anni effin,

the rulers in either direction from a rectangle may be f i z', may, therefore, be nicely adjusted by the use yofL4 Gains H H. This adjustment of the straight-edge b' other hand it also provides the means of' clamping the rent being thus enabled to secure the rnleriliigidly so guided as to require no effort to maintain its paral- Drdinarily, thesel v'ndmable feet may occupy the po. s ition shown in full lines in Eg. 1; but, when the rulers D E are topbe usedwith any considerable degree-of Obliquity near the lower edge of the board, the one of the feet 'm which would, if permanent, check the required downward motion of theroller, need only be drawn out, as shown in dotted lines in iig. l, to give the desired clearance.

The combination of a system of' scales with the above-described mode of maintaining parallel guiding,r surfaces will' be fully understood on reference to iig. 1 in the drawing, and the convenience and practical importa/nee of this improvement will at once be evident.

The ruler E, being easily reversible on pins e e, may have several edges graduated, and thus contain a variety ofsoales for horizontal distances andvertical lines.

Graduations of conforming values are provided atV the right and left-hand sides of the board for the vertical distances and horizontal lines. v

The scales on the right-hand side are shown on the clamping-strip N, (hereafter fully described,) and those on the left-hand side are represented as being printed on the margin of the drawing-paper.

The degree-scale may be either on the protractor F, or it may be provided alongside of each of vthe vea tical scales, as shown to the left hand 'of g. il.

The saving of much tedious labor, and the' accuracy of workmanship resultingl from the use oi'- this system of scales, is very importantz' To draw a screw or rack, for instance, requiring along series of correcilyspaeed equidistant lines, it is necessary with the ordinary drawing implements to rst divide and mark the spaces carefully with the compasses, then to draw the lines in pencil, and finally in ink, white by the use of my improvement such spaces can be directly and accurately defined from one of the graduations and at once drawn in ink, without the tedious preparation otherwise required. l l

Having thus described .the nature and objects of my invention,

I claiin- The rulers D E, head G, and guides bb', when wmbined with and arranged iu relation to a drawing-board, inthe manner and for the purpose specified.

, THEODORE BERGN ER.

Witnesses COLEMAN SELLERS, GRAS. W. PEALE. 

